Stainless steel is generally heavier than aluminum alloy. This is due to the differences in their densities. Stainless steel has a density of approximately 7.8 grams per cubic centimeter (g/cm³), while aluminum alloy typically has a density ranging from 2.6 to 2.8 g/cm³. As a result, aluminum alloy is lighter than stainless steel. For instance, a 1-inch cube of aluminum alloy weighs significantly less than a 1-inch cube of stainless steel. This difference in weight is crucial in various applications, such as in the aerospace industry, where the use of lightweight materials is essential for fuel efficiency and performance.